A backyard in Iowa has become an excavation site after a family went blackberry-picking behind their house two years ago and came back with a prehistoric mammoth femur.

A man identified only as John discovered the bone when one of his sons saw what he believed to be a ball while walking in the forest behind their property in 2010, according to local Des Moines’ affiliate WOI.

John, who is interested in archeology, quickly realized that the object wasn’t a toy.

“I got down on my hands and knees on the bank, and I could see a marrow line around the edge of this, and I said, ‘Boys, that’s a bone. That’s a really big bone,” John told ABC5.

Although he discovered the 4-foot-long femur nearly two years ago, John just recently brought the massive bone to the University of Iowa to be identified.

Scientists are the university, said that they were going to try to extract DNA from the bone and clone the mammoth. “We hope to have a wooly mammoth walking around Des Moines, by the end of 2013, maybe sooner,” said Jacob Marx, head of the Genetics Department at Iowa.

The university’s Museum of Natural History is leading the backyard excavation. Volunteers from the University of Iowa and Iowa State University have so far found the mammoth’s feet bones and thoracic ribs, in addition to its femur.

While it is not unusual to find mammoth fossils in Iowa, it is rare to find so many bones belonging to the same animal in the same place.

Sarah Horgen, the museum’s education coordinator, said the mammoth went extinct by the end of the last ice age and is at least 12,000 years old.

“It’s pretty exciting – partially because the mammoth is being discovered where it died,” Horgen told ABC News. “We know that because we’re finding very large bones right alongside very small bones.”

For now, the bones are resting in John’s living room until he figures out what to do with them.

“Build another room off the side of the home and put it together?” John said when ABC5 asked what his plans were.

John may have more bones to add to his collection. Volunteers predict that they will unearth the mammoth’s head by the end of the summer.